1. Field of the Invention
This invention relates to devices for preventing auto theft and particularly to a device that locks onto the wheel of an automobile and punctures the tire if the device is moved.
2. Prior Art and Information Disclosure Statement
A number of devices have been disclosed for deterring theft of a vehicle either by sounding an alarm or disabling the vehicle in some manner. Most of these devices are employed inside the vehicle and can therefore be tampered with and defeated in the relative seclusion of the vehicle's interior. Devices have been disclosed for disabling a vehicle by the application of a clamp-like device to one of the vehicle's tires rendering the vehicle difficult to drive. Some of these devices also employ a pointed member which punctures the tire if any attempt is made to move the vehicle. This type of device is effective because it is visible from outside the vehicle and any attempt to defeat it must be done in full view of bystanders. These external devices however are typically heavy, bulky and difficult for the owner to install or remove. In addition, these devices include locking mechanisms which are at least exposed. State-of-the-art criminals are able to freeze the lock using cryogenic liquids an then break them with a few sharp blows of a hammer.
For example, U.S. Pat. No. 3,907,072 to Shafer is for a chock block having a pair of arms for engaging a tire, one of the arms being adjustable and locked in position so that any size tire can be engaged. This device could be pried from the tire with a crowbar. The locking mechanism is located in a position where cryogenic fluid can be readily applied to break the lock.
U.S. Pat. No. 4,164,131 to Desmond et al is for a tire clamp formed of a pair of pivoting arms which may be manually closed and locked upon opposite sides of the tire. The locking mechanism for this device is remote from the tire and configured for easily breaking particularly if cryogenic liquids are applied.
U.S. Pat. No. 4,651,849 to Givati is for a pair of frames pivotally attached to one another providing that combined frames may be positioned with three points of contact around the tire and locked in position. The device can be used for only one tire width.
U.S. Pat. No. 4,854,144 to Davis is for a collapsible lockable frame that engages three locations around the tire. The device has no provisions for accomodating various widths of tires.
U.S. Pat. No. 4,441,586 to Bernier is for a springloaded clamp with jaws pivotally attached to one another that can be manually separated to fit around a tire. An adjusting bolt limits degree of pivotal movement of the jaws to accomodate to a range of tire widths and secure the device in position. A strap is hingably attached and padlocked over the bolt to prevent access to the adjustment bolt. This device requires a separate wrench to adjust the bolt. Padlocks are notoriously easy to cut with bolt cutters.
Japanese patent 58-76438 is for a a pair of opposing clamp jaws secured together by a lockable ratchet. One jaw spans across the outside surface of the entire hub of the wheel and the opposing jaw contacts the hub on the inside of the wheel. This arrangement is such that no part of either clamp nor any part of the clamp contacts the tire so that protection against unauthorized movement of the vehicle depends entirely on the difficulty of removing (prying) the device from the tire.